Though used increasingly widely, LED lighting fixtures still have several drawbacks, mainly due to the intrinsic characteristics of the LED light source.
To begin with, a LED is a substantially spot, or at any rate very small, source; so, to obtain a large, possibly homogeneous, lighting surface, as required in some applications, a multiple-LED arrangement is needed, thus increasing the cost and complexity of the LED power and control circuits.
Moreover, LED sources used for lighting purposes may give rise to glare phenomena.
Also, adequately collimating the light beam emitted by the LEDs normally calls for the use of optical systems that are relatively complex and/or bulky—especially in length (along the optical axis of the system).